JPH09162276A - Wafer carrier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wafer carrier which is capable of protecting a semiconductor wafer against charge-up damages and surge damages caused by static electricity and physical defects caused by the reduction in mechanical accuracy. SOLUTION: A wafer carrier 1 is formed of high molecular synthetic resin material which is similar to polypropylene and formed through the polymerization of conductive molecules and polypropylene polymer which is as rigid as polypropylene and conductive. The wafer carrier 1 is used for housing or transferring silicon wafers, whereby dusts are prevented from adhering to the carrier 1 and the silicon wafers due to static electricity. The wafer carrier 1 and the silicon wafers are restrained from being charged with static, whereby semiconductor devices provided onto the silicon wafer are protected against charge-up damages and surge damages caused by static.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer carrier used for storing and carrying a semiconductor substrate in a semiconductor device manufacturing process.

[0002]

2. Description of the Related Art In recent years, contamination of a silicon wafer with dust from a wafer carrier and charge-up breakdown and surge breakdown due to static electricity due to electrostatic charging of the wafer carrier have been associated with semiconductor device miniaturization. It has come to greatly affect the yield. In addition, due to a sharp rise in the unit price of wafers, physical defects of silicon wafers frequently occur due to transport troubles due to mechanical accuracy deterioration due to time-dependent deformation and impact deformation of low-rigidity wafer carriers such as fluorine-based synthetic resin materials, The processing yield is decreasing.

Conventionally, from the viewpoint of preventing heavy metal contamination of a silicon wafer, a fluorine-based synthetic resin material such as ethylene trifluoride or ethylene tetrafluoride that does not cause contamination of a silicon wafer, which is a semiconductor substrate, by a material. Also, a wafer carrier has been manufactured from a synthetic resin material such as polypropylene and a high molecular compound, and has been used for storing and carrying a silicon wafer, which is a semiconductor device substrate material.

These conventional wafer carriers are manufactured with an emphasis on prevention of contamination, and much less attention is paid to the static charge characteristics and mechanical rigidity against time-dependent deformation, impact deformation and the like. There wasn't. Therefore, a non-conductive fluorine-based synthetic resin or the like has been recommended as a constituent material of the wafer carrier (eg, JP-A-63-38).
No. 240).

[0005]

However, since the fluorine-based synthetic resin material, polypropylene, and the like are easily charged with static electricity, the wafer carrier itself produced by the static electricity may cause an adsorption phenomenon of floating dust. , The transfer of dust to the silicon wafer housed at the end of the wafer carrier may occur (Example:
JP-A-4-64246). In addition, the static electricity charged on the wafer carrier itself charges the silicon wafer with static electricity, causing charge-up breakdown of the semiconductor device on the substrate and surge breakdown due to abrupt discharge. Further, since the wafer carrier made of a fluorine-based synthetic resin material has a lower rigidity than those made of other synthetic resin materials, it is easily deformed due to its own weight over time, and it is added from the outside when the silicon wafer is transferred. There is an inconvenience in that the silicon wafer is easily deformed by the impact applied and causes interference due to mechanical displacement of the contained silicon wafer, resulting in physical damage of the silicon wafer.

According to the present invention, the rigidity of a high-rigidity resin material such as polypropylene is used, and the conductive wafer is made of a conductive synthetic resin material whose electrostatic chargeability is greatly improved. It is an object of the present invention to provide a wafer carrier capable of preventing electrostatic damage utilizing the characteristics of conductivity and preventing physical damage due to silicon wafer transfer troubles by preventing time-dependent deformation and impact deformation of the wafer carrier. Is.

[0007]

According to the present invention, a synthetic resin wafer carrier used in a semiconductor device manufacturing process is a conductive polymer synthetic resin wafer carrier having both conductivity and high rigidity. As a result, charge-up breakdown due to static electricity of the semiconductor device, surge breakdown, and physical loss due to mechanical precision deterioration are reduced, and the semiconductor device yield and the silicon wafer processing yield are improved.

[0008] Specifically, the rigidity of polypropylene having excellent mechanical properties is maintained as it is, and a polymer synthetic resin material similar to polypropylene in which conductive molecules are polymerized at the time of polymerization of polypropylene polymer (hereinafter referred to as "conductive polypropylene similar material"). “)) To form a wafer carrier.

By using a wafer carrier formed of a conductive polypropylene-like material for storing and carrying a silicon wafer, dust adsorption due to static electricity on the wafer carrier itself is prevented, and transfer adhesion of the dust to the silicon wafer is prevented. In addition, the electrostatic charge of the wafer carrier is prevented and the electrostatic charge of the silicon wafer is prevented, so that charge-up breakdown and surge breakdown due to static electricity of the semiconductor device on the silicon wafer substrate are prevented.
On the other hand, the high rigidity equivalent to that of polypropylene material prevents the wafer carrier from being deformed with time and shock. As a result, physical damage of the silicon wafer can be prevented, and an effect of improving the processing yield of the semiconductor device by erasing the physical damage of the silicon wafer due to the transport trouble due to the time-dependent deformation and impact deformation prevention of the wafer carrier is derived. It will be.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is a wafer carrier 1 for containing a silicon wafer as represented by FIG.
By using a wafer carrier 1 made of a polypropylene-like polymer synthetic resin material obtained by polymerizing conductive molecules at the time of polymerizing a polypropylene polymer having conductivity while maintaining the rigidity of polypropylene, the wafer carrier 1 is used for storing and carrying a silicon wafer. The carrier 1 itself was prevented from attracting dust due to static electricity, and the dust was prevented from adhering to the silicon wafer. Moreover, by preventing the electrostatic charge of the wafer carrier 1 and the electrostatic charge of the silicon wafer, it is possible to prevent charge-up breakdown and surge breakdown due to static electricity of the semiconductor device on the silicon wafer substrate. On the other hand, the high rigidity equivalent to that of the polypropylene material can prevent the wafer carrier 1 from being deformed with time and impact. As a result, physical damage to the silicon wafer can be prevented.

With reference to Table 1, the following will describe the state of adhesion of floating dust to a silicon wafer by the present invention and the conventional wafer carrier, its electrostatic charge state, and mechanical strength.

Regarding the electrostatic charging characteristics, the electrostatic charging voltage measuring device (TREK341) manufactured by Trek Japan Co., Ltd. is used in an environment where an electrostatic neutralizing mechanism such as an ionizer is not used.
The maximum value of the actual measurement data of the electrostatic charge state on the wafer carrier measured by using. The number of adhered suspended dusts is shown in the range of the maximum value and the minimum value of the actual measurement values measured by a laser surface foreign matter inspection device (SurfScan6400) manufactured by Tencor, USA when latex particles having a diameter of 300 nm are forcibly adhered. For mechanical strength (elasticity) and specific gravity, material nominal data (according to Japan Bulker) are shown.

[0013]

[Table 1]

Generally, the allowable charging withstand voltage of the gate electrode portion of a transistor of a MOS type semiconductor device on a silicon wafer is ±
It is 1 kV, and the charging voltage of the conductive polypropylene-like material is a sufficiently low value. In addition, the degree of adhesion of floating dust due to a decrease in electrostatic charging voltage was also improved by a factor of 5 to 20 compared to the fluorine-based synthetic resin material. As a result, the risk of defect occurrence in the semiconductor device due to charge-up breakdown or surge breakdown due to static electricity is eliminated, and the risk of defect occurrence in the semiconductor device due to floating dust is reduced from 1/5 to 1/20. . Also,
Regarding mechanical strength, it is three times stronger than fluorine-based synthetic resin materials, and its specific gravity is also sufficiently small, so the risk of deformation due to its own weight and the risk of deformation due to impact such as dropping are reduced, and transport problems The factor of mechanical deterioration due to the deformation of the carrier that causes the above is significantly improved.

According to the above-mentioned example, since the wafer carrier 1 is made of a highly rigid conductive polypropylene-like material, the electrostatic charge characteristics and the adhesion of floating dust to the silicon wafer are improved, and the synthetic resin is excellent in mechanical rigidity. It is possible to give the same rigidity as polypropylene, which is the material, and electrostatic charge, which is a factor that reduces the yield of semiconductor devices on the silicon wafer substrate and the processing yield of the silicon wafer itself, and transport problems due to deformation The physical deficiency due to the above can be greatly improved.

In the above example, the conductive polypropylene-like material is used for the wafer carrier 1 and the description is limited to the semiconductor device. However, similar to the semiconductor device, the electronic device device substrate accompanied by ultra-fine processing in which static electricity and floating dust are disliked, For example, glass substrates for liquid crystals, solar cells, plasma display devices, optical discs, magnetic discs, magneto-optical discs, and other non-metallic or metallic substrate wafers, semiconductor device wafers using substrates other than silicon, and semiconductor device manufacturing processes. It is obvious that it is also useful as a wafer carrier for accommodating and transporting wafers for substrates such as micromachines to which is applied. Also, the case where a conductive polypropylene-like material is used as the conductive material has been described, but carbon whiskers, carbon fibers, conductive ceramics,
It has been found that even a conductive resin material containing whiskers or the like can obtain substantially the same effect with respect to electrostatic charging, and thus those materials may be used.

[0017]

According to the present invention, since the material of the wafer carrier for accommodating and transporting the apparatus substrate wafer is a highly rigid conductive material such as a material similar to conductive polypropylene, electrostatic breakdown and adsorption of floating dust due to electrostatic charging. Greatly improve the yield reduction factors of semiconductor devices on silicon wafer substrates such as physical defects of silicon wafers due to deterioration of mechanical accuracy due to contamination, time-dependent deformation, impact deformation, etc. be able to.

[Brief description of the drawings]

FIG. 1 is a perspective view of an example of an embodiment of a wafer carrier of the present invention.

[Explanation of symbols]

 1 Wafer carrier

Claims (1)

[Claims] 1. A wafer carrier used for accommodating and carrying a silicon wafer, wherein the wafer carrier is made of a conductive synthetic resin material.